To address the airborne transmission mode of SARS-CoV-2 air samples were collected in the largest hospital in Iran. • Our results indicated that all collected samples were negative in terms of the viral RNA. • We did not detect any positive readings 2 m from the patients' beds.

Summary. -Parvovirus B19 (B19V) is a small non-enveloped single-stranded DNA (ssDNA) virus of the family Parvoviridae, the subfamily Parvovirinae, the genus Erythrovirus and Human parvovirus B19 type species. It is a common community-acquired respiratory pathogen without ethnic, socioeconomic, gender, age or geographic boundaries. Moreover, the epidemiological and ecological relationships between human parvovirus B19, man and environment have aroused increasing interest in this virus. B19V infection is associated with a wide spectrum of clinical manifestations, some of which were well established and some are still controversial, however, it is also underestimated from a clinical perspective. B19V targets the erythroid progenitors in the bone marrow by binding to the glycosphingolipid globoside (Gb4), leading to large receptor-induced structural changes triggering cell death either by lysis or by apoptosis mediated by the nonstructural (NS)1 protein. The pattern of genetic evolution, its peculiar properties and functional profile, the characteristics of its narrow tropism and restricted replication, its complex relationship with the host and its ample pathogenetic potential are all topics that are far from a comprehensive understanding. The lack of efficient adaptation to in vitro cellular cultures and the absence of animal models have limited classical virological studies and made studies on B19V dependent on molecular biology. The present review looks at the nature of this virus with the view to provide more information about its biology, which may be useful to the present and future researchers.Keywords: human parvovirus B19; respiratory pathogen; biology; genome; fifth disease; transient aplastic crisis; anemia * Corresponding author. E-mail: rezaie@tums.ac.ir; phone: +982188982343. Abbreviations: B19V = parvovirus B19; Gb4 = glycosphingolipid globoside; IL-6 = interleukin 6; IVIG = intravenous immunoglobulin G; MHC = major histocompatibility class; SF3-helicase = superfamily 3 helicase; NS = nonstructural; TNF-α = tumor necrosis factor α; VLPs = virus like particles; VP1 = viral protein 1; VP2 = viral protein 2

Human Parvovirus B19 (B19V) is a prototype of the Erythroparvovirus genus in Parvoviridae family. B19V infections are often associated with fever and rash, and can be mistakenly reported as measles or rubella. Differential diagnosis of B19V illness is necessary for case management and also for public health control activities, particularly in outbreak situations in which measles or rubella is suspected. To investigate the causative role of B19V infection in children with measles- and rubella-like illness, a total of 583 sera from children with exanthema were tested for presence of B19V by determining anti-B19V IgG and IgM antibodies by ELISA as well as B19V DNA detection by nested PCR. DNA positive samples were assessed further for determination of viral load and sequence analysis by Real-Time PCR and Sanger sequencing method, respectively. Out of 583 patients, 112 (19.21%) patients were positive for B19V-IgM antibody, 110 (18.87%) were positive for B19V-IgG antibody, and 63 (10.81%) were positive for B19V viral DNA. The frequency of B19V-IgG antibodies were increased with age; that is children under 6 year old showed 7.11% seroprevalence for B19V-IgG as compared to 18.39% and 28.91% for age groups 6 to >11 and 11-14 years old, respectively. Phylogenetic analysis of the NS1-VPu1 overlapping region revealed that all sequenced B19V-DNA belonged to genotype 1. The results of this study may aid the surveillance programs aiming at eradicating measles/rubella virus in Iran, as infections with B19V can be mistakenly reported as measles or rubella if laboratory testing is not conducted.

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Background SARS‐CoV‐2 genomic surveillance is necessary for the detection, monitoring, and evaluation of virus variants, which can have increased transmissibility, disease severity, or other adverse effects. We sequenced 330 SARS‐CoV‐2 genomes during the sixth wave of the COVID pandemic in Iran and compared them with five previous waves, for identifying SARS‐CoV‐2 variants, the genomic behavior of the virus, and understanding its characteristics. Methods After viral RNA extraction from clinical samples collected during the COVID‐19 pandemic, next generation sequencing was performed using the Nextseq and Nanopore platforms. The sequencing data were analyzed and compared with reference sequences. Results In Iran during the first wave, V and L clades were detected. The second wave was recognized by G, GH, and GR clades. Circulating clades during the third wave were GH and GR. In the fourth wave, GRY (alpha variant), GK (delta variant), and one GH clade (beta variant) were detected. All viruses in the fifth wave were in GK clade (delta variant). In the sixth wave, Omicron variant (GRA clade) was circulating. Conclusions Genome sequencing, a key strategy in genomic surveillance systems, helps to detect and monitor the prevalence of SARS‐CoV‐2 variants, monitor the viral evolution of SARS‐CoV‐2, identify new variants for disease prevention, control, and treatment, and also provide information for and conduct public health measures in this area. With this system, Iran could be ready for surveillance of other respiratory virus diseases besides influenza and SARS‐CoV‐2.